(PHP 5 >= 5.2.0, PHP 7) Returns the error code of the last PCRE regex execution

(PHP 4, PHP 5, PHP 7) Binary safe case-insensitive string comparison

(PHP 4, PHP 5, PHP 7) Finds the length of the initial segment of a string consisting entirely of characters

(PHP 4, PHP 5, PHP 7) Return information about characters used in a string

(PHP 5, PHP 7) Find the position of the last occurrence of a case-insensitive substring in a string

(PHP 5 >= 5.3.0, PHP 7) Convert a 8 bit string to a quoted-printable string

(PHP 4 >= 4.0.5, PHP 5, PHP 7) Get numeric formatting information

(PHP 4, PHP 5) Make regular expression for case insensitive match

(PHP 4, PHP 5, PHP 7) Make a string lowercase

(PHP 5 >= 5.3.0, PHP 7) Parse a CSV string into an array